Fluid-pressure-operated tool.



PATBNTED AUG. 1, 1905.

o. H. JoHNsoN.'l

' FLUID PRESSURE OPERATED TOOL.4 APPLICATION FILED we. 5, 1902. BENWBDJUNE 24, 1905.

uNITnn STATES .PATENT oFF-Ion.

CHARLES H. JOHNSON, OF CHICAGO HEIGHTS, ILLINOIS.

FLUlD'PRESSURE-QPERATED TOOL.

Speci-nzation of Letters Patent.

Application filed August 5, 1902. Renewed June 24, 1905.. Serial No.266,848.

T0 all whom may concern.:

VBe it known that I, CHARLES H. JOHNSON, a

citizen of the United States, residing at Chicago Heights, county ofCook, State of Illinois, have invented a certain new and usefulImprovement in Fluid Pressure Operated Tools; and I declare thefollowing to be a full,

clear, and exact description of the invention, such as will enableothers skilled in the art to which it pertains to makeA and use thesame, reference being had tothe accompanying drawings, which form a partof this specification.

My invention relates generally to fluidpressure operated tools, and moreparticularly to valve mechanism controlling the admission and exhaust offluid-pressure tothe cylinder.

lnfluid-pressure tools it is desirable that the valve controlling thesupply and exhaust of pressure to the ends of the cylinder should beoperated to cut ofl" the supply from the respective sides of 'the pistonbefore it reaches the end of its stroke, and it issalso desirablethatvthe valve` should be quickly shifted from .oneposition to the otherand when shifted` positively held by a preponderance `of pressurein eachposition until the piston reaches the ,predetermined point in itsstroke, when thesupply and exhaust of fluid -pressure to ,the respectiveends of .the cylinder should be reversed.

An object of my invention is to provide a -iiuid-pressure-operated .toolin which the suplply and exhaustnof pressureto the respective ends ofthe cylinder are controlled by a pis- `ton-valve, the reciprocation ofwhich to its controlling positions will be quickly and certainlyaccomplished, and which when shifted will be firmly held in eachposition until again shifted by the piston reaching the properpredetermined point in its throw.

.A further object of my invention is to provide in aliuid-pressure-operated tool a valve mechanism for controlling thesupply and exhaust of huid-pressure to the opposite ends of the cylindercomprisinga differential pistonvalve which will -be Iretained inposition to ad mit fluid-pressure to one end of the cylinder by thepressure of iuid exhausting from the other'end offthe cylinder and whichwill be automatically moved to its other position when the 'pressure ofthe exhaust iuid is overbalanced by Huid-pressure constantly exertedupon annular radial' surfaces o f the valve.

A still furtherl objectpf my invention is t0 provide a iiuid-pressurV,operated tool yof the .character-referred to which will be simple inconstruction, inexpensive in manufacture, and eiiicient in operation.

The embodiment of my invention herein disclosed, generally described,-comprises a valve mechanism controlling the supply and exhaust ofiuid-pressureto opposite ends of the cylinder to reciprocate the pistontherein and`consisting in a differential piston-valve the movement ofwhich to one position is effected by exposing an end thereof to theliuidpressure in the back end of the cylinder, the valve being retainedin vsuch position by the fluid-pressure passing from the back end of thecylinder to an exhaust-port, while the movement of the valve to and itsretention in .its other position are effected by pressure iiowingdirectly from the supply-port exerted on differential annular surfaces.

My invention will be morefully described hereinafter,with reference tothe accompanyingA drawings, in which the same is illustrated as embodiedin a convenient and practical form, and inwhic'hi Figure 1 is ahorizontal central section through the cylinder with the parts which fitwithin the cylinder shown in plan; Fig. 2, a ycross-sectional view, onan enlarged scale, showing the valve mechanism, taken on line 2 2, Fig.1; and Fig. 3, aview similar to Fig. 2, showing the valve in section andin a position opposite to that shown in Fig. 2.

Similar reference characters are used to indicate similar parts in theseveral figures of the drawings.

Reference-letter A indicates the handle of l and adapted to be engagedbetweenthe end lof the cyinder C and a flange formed on thecylinder-head C', as clearly shown in Fig. 1. YA4c indicates a lever forunseating a throttle-valve. The latter, however, is not shown, as thesame forms no part of my present invention. l v

The cylinder C is providedwith a bushing c, one end of which` is engagedby the tubular projection C2 of the cylinder-head C. The part C2 ispreferably exteriorly screwthreaded to engage scrfew threadsformcdWithin the end of the cylinder C, and thereby i retain thecylinder-head, as well as the handle A, in position on the cylinder.

The end C5. of the cylinder is interiorly screw-threaded and is engagedbya ferrule G. A snap or die H is removably supported within the ferruleGr, in which it is yieldingly retained by means of a spring-ring g,seated within an annular groove formed in the interior surface of theferrule. rlhe shank of the die H is reduced, as shown at L, therebyforming shoulders to serve as stops to limit the movement of the diethrough engagement with the spring-ring g. A chamber C4 is formed in theend of the cylinder between the ferrule and the end of the bushing o,within which is located a button L, having a reduced portion L of adiameter substantially the same as the interior diameter of the ferrule,Within which it extends. An exhaustport Z leads from the chamber C4 andis closed by the button L, as shown in Fig. l, when the die is inengagement with an object. A

groove Z2 is formed in the interior wall of the chamber C4 to permitfluid-pressure to pass around the head of the button. The tension of thespring C3, which is located between the bushing c and the cylinder C,tends to move the button L, so as to open the exhaustport Z.

A cylindrical valve-casing A2` is located transversely beneath the backend of the cylinder and is preferably formed integrally with the handleA. The valve-casing is provided with a series of annular grooves, withwhich communicate ports ct', ai, and a3, registering with ports c', c2,and c3, formed in the cylinder C. An exhaust-port a* communicates withan annular passage formed between the end of the cap A5 and thevalve-casing. The end of the casing opposite to the cap A5 is providedwith a circular opening a5 in constant communication with theatmosphere. An annular supply-passage a is formed near the center of thevalve-casing and communicates with a source of fluid-pressure, suchcommunication being controlled, as is customary, by a throttle-valve ofany desired construction.

The port c communicates with a passage leading to a point Within thecylinder slightly farther away from the chamber C than the length of thepiston K, as shown in Fig. 1. The port 02 communicates with the back endof the cylinder. The port c3 is extended to form a passage, whichcommunicates with the front end of the cylinder, as shown in Fig. l.

`A bushing E is located within the valvecasiiig A2 and is retainedincontact with a cir` cular flange around the opening a5 by means of thescrew-threaded cap A5. The bushing is provided with a series of ports e,e', e2, e3, and et, which register with the corresponding ports e, e,a2, a3, and ai, formed in the valvecasing. A circular opening e5 isformed in the end of the bushing opposite to the cap A5 and ispreferably concentric with the opening e5.

A differential piston-valve D is located within the bushing and controlsthe ports therethrough. The end D of the valve is hollow and is providedwith ports d', connecting the exterior surface of the valve with thehollow interior. An annular flange D4 is formed on the valve at a pointintermediate of the hollow end D and the opposite closed end D of thevalve. A restricted passage (Z is formed through the radial flange D4.An annular flange is formed around the end D2 of the valve and is of adiameter slightly less than the exterior diameter of the end D'. The endof the bushing E is reduced in bore to conform to the diameter of theilange around the end of the valve D2.

The several parts of the valve mechanism may be readily assembled andthe valve easily removed from the bushing owing to the screwthreadedengagement between the cap A5 and the corresponding end of thevalve-casing.

The operation of my invention is as follows: When the valve is in theposition indicated in Fig. 2, fluid-pressure flows from thesupply-porte, through the ports e in thebushing, around the reducedportion of the valve between the shoulder D3 and the annular flange Di,through ports e2, a?, and ci, to the backend of the cylinder. As thefront end of the cylinder is in communication with the atmospherethrough ports c3, a", e, e, and (t5, hence the piston is moved towardthe front of the tool and delivers a blow upon the button L, whichcommunicates the impact of the piston to the snap or die H. When thepiston has nearly reached the limit of its forward stroke, the port c4is uncovered and fiuidpressure iiows through the passage communicatingwith such port to the port c', thence through the port d in thevalve-casing, the ports e iu the bushing, through the ports (l, to thehollow interior of the end D of the valve. The Valve is consequentlymoved from the position shown in Fig. 2 to that shown in Fig. 3,inasmuch as the area of the end D is greater than the areas exposed topressure tending to retain the valve in the position shown in Fig. 2.When the valve is in the position indicated in Fig. 3, the back endofthe cylinder is placed in communication with the atmosphere throughthe following ports and passages: c2, afi, a, d', ai, and a4.Fluid-pressure is then admitted to the front end of the cylinder to movethe piston toward the back or handle end of the tool through thefollowing ports and passages: a, e, dc, w3, and c. rlhe valve l) isretained in the position shown in Fig. 3 owing to the pressure of theexhausting fluid exerted on the end D' thereof, the degree ol suchpressure and its duration being regulated by the size of theexhaust-port a4 with respect to the size of the ports c2, a, and b2.

When

the fiuid has exhausted from the back end of the cylinder and is nolonger exerted on the exterior of the end Dl or' the valve, the latteris moved from the position shown in Fig. 3 to that shown in Fig. 2,owingto there being a greater area normally exposed to pressure tendingto move the valveto the position shown in Fig. 2. This normal tendencyofthe valve is due to the fact that the annular shoulder D3 is the samein area as the opposite surfacev of the flange D4, and consequentlybalances the same, while the area of the other surface of the flange D4Lis greater than the area ofthe flange around the end D2 ofl the valve. lIt is therefore evident that the Valve will be moved to andA retained inthe position shown in Fig. 2 Whenever thel exterior surface of the end Dof the valve is exposed to atmospheric pressure and that the valve willonly bev moved to and retained in the position shown in Fig. 3

when the area of the end D is exposed to suf-V ficient pressuretooviercomel the diiiierence in area between ythe flange D4 and theliange around the end D2 of the valve. When the snap Vor die is lforcedagainst an object, the spring C3 is compressed, owing tothe engagementbetween the adjacent end sofv the die H and the reducedportion L of the,button L, as shown in Fig. l. The exhaust-port 'Z' is consequentlyclosedwhen the button L is in position to receive the impactof thepiston and communicate the same to Vthedie H. When, however', thesnapvorvdie is outof contact with an object, the spring C3 expands,thereby forcing the piston'and die outwardly, so as to uncover theexhaust-port Z and permit the luidlunder pressure to flowfrom theA frontend of the cylinder tol theatmospliere, and thereby discontinue thereciprocation of the piston. The expansion oi' the spring C3 moves thehead of the button'into engagement with the inner end of the ferrule,Gand consequently prevents the impact of the piston 4from ejectingtheldie from thektool when not in contact with an object, The port Z4isrestricted so that the movement of the piston toward the` mitfluid-pressure to one end of the cylinder by the pressure of tlieliuidexhausting from the other end thereof and is vautomatically movedto itsother position4 upon the escape of the exhausting fluid by pressureflowing dircctlyv through the supply-port. i

While iI have describedmore or: less precisely the'details ofconstruction, 'Ildo'not wish to'be understood as limiting myselfthereto, as I contemplate changes inform, theproportion lof parts, andthe substitution of equivalents as circumstances may suggest or renderexpedient without departing from the spirit of my invention. y

I-Iavingnow -fully described my invention, what I claim as'new, anddesire to secure by Letters'Patent, is

l. In a 'luid-pressure-operated tool, the coin'- bination withacylinder, of ay reciprocating piston therein, a valve-casing having anopen end communicating with theatmosphereand having ports communicatingwith the oppolsite ends of the cylinder, a differential piston-valvelocated in said casing controlling the supplyand exhaust offluid-pressure, said cylinder and valve-casing having ports and passageswhereby said valve is retained in position to admit Huid-'pressure toone end of the cylinder by the 'pressure of the fluid exhausting fromthe other end of the cylinder.

2. In a fluid-pressure-operated'tool,the cornbination with a cylinder,of a reciprocating piston therein, a valve-casing having ports thecylinder, the pressure of the exhausting iiuid retaining the valve insaid position, and j radial annular surfaces on said valve constantlyexposed to fluid-pressure to lmove the i valve and retain it in itsreverse position.l t 3. In ailuid-pressure-operated tool,the com-4bination with a' cylinder, or' a reciprocating piston therein, a valvecasing having ports communicating with the ends of said cylinder,

a piston-valve controlling the ports in said j 'casing and havingannular radial surfaces constantly exposed to pressure from thesupplyport tending to move the valve into position i to admit pressureto the back end of the cylinder, said vcylinder having a port controlledend of the cylinder and to exhaust pressure through the valve-casingfrom the back end -I of the cylinder, the valve being retained in suchlposition by the 'pressure of the exhaustl' `ing Huid and beingautomatically reversed when the pressure from the supply-port upon theannular radial surfaces overbalances the pressure of theexhaustingiiuid.

4. In atiuid-pressure-operated tool,the combination with a cylinder, ofa reciprocating a piston-'valve controlling the ports in said 'casingand having radial surfaces constantly exposed to pressure from thesupply-port tending tO move thevalve'into position to' admit pressure tothe back end of the cylinder, one of said radial surfaces having arestricted port through which pressure passes to the front end of thecylinder and two of said radial surfaces forming a passage for thefluid-pressure to the back end of the cylinder, said cylinder having aport controlled by the piston and communicating with one end of thevalve-casing to move the valve into position to admit fluid-pressure tothe front end of the cylinder and to exhaust pressure through thevalve-casing from the back end of' the cylinder, the valve beingretained in such position by the pressure of the exhausting fluid andbeing automatically reversed when the pressure from the supply-port uponthe radial surfaces over-balances the pressure of' the exhausting fluid.y

5. In afluid-pressure-operated tool,the combination with a cylinder, ofa reciprocating piston therein, a valve casing having exhaustports atits opposite ends, a supplyport near the center thereof and portscommunicating with the opposite ends of the cylinder, said valve-casingalso having a port between one of the exhaust-ports and a port leading'to the back end of the cylinder communicating with the interior of thecylinder at a point distant from its front end slightly greater than thelength of the piston through which fluid-pressure flows from thecylinder to reverse the valve, a differential pistonvalve within theValve-casing controlling said ports, said valve being moved in a reversedirection and retained therein by the pressure of fluid flowing directlyto the valve-casing` from the supply-port.

6. In afiuid-pressure-operated tool,the combination with a cylinder, ofa reciprocating piston therein, a valve-casing having portscommunicating with the opposite ends of the cylinder, a differentialpiston-valve controlling said ports and having annular radial surfacesconstantly exposed to fluid-pressure flowing from the supply-porttending to move the valve to and retain it in position to admitiiuidpressure to the back end of the cylinder, the valve being movedinto position to admit fiuidpressure to the front end of the cylinder byfluidpressure Yadmitted to the valve-casing from the back end ofthecylinder and retained in such position by the pressure of the liuidexhausting from the back end of' the cylinder.

7. In a fluid-pressure-operated tool, the combination with a cylinder,of a reciprocating piston therein, a valve-casing having portsconimunicating with the opposite ends of the cylinder, a differentialpiston-valve controlling said ports and having a hollow end and annularradial surfaces constantly exposed to fluidpressure iiowing from thesupply-port tending to move the valve into and retain it in position toadmit fluid-pressure to the back end of the cylinder the valve beingmoved into position to admit fluid-pressure to the front end of thecylinder by Huid-pressure admitted to the valve-casing from the back endof the cylinder and retained in such position by the pressure of theexhausting fluid passing through the hollow end of the piston from theback end of the cylinder.

8. In afluid-pressure-operated tool,the combination with a cylinder, ofa reciprocating piston therein, a valve-casing having portscommunicating` with the opposite ends of the cylinder, a differentialpiston-valve having four annular radial surfaces between two of' whichfluid-pressure passes to one end of the cylinder, such valve also havinga restricted passageleading to the space between the other two radialsurfaces through which iiuid-pressure liows to the other end of thecylinder.

9. In a fluid-pressure-operated tool,the combination with a cylinder, ofa reci procating piston therein, a valve-casing having portscommunicating with the opposite ends of the cylinder, a differentialpiston-valve having ends ofdifferent diameters and an intermediateradial flange forming annular passages between the same and enlarged endfor the passage of Huid-pressure to one end of the cylinder, said flangehaving a restricted passage through which fluid-pressure flows to theother end of the cylinder, said valve-casing having exhausting-portsadapted to be placed in communica-- tion with the ports leading to theends of the cylinder by the ends ofl the valve.

l0. In a Huid-pressure-operated tool, the

. combination with a cylinder, a reciprocating piston therein, avalve-casing having exhaustports at the opposite ends thereof', asupplyport at substantially the center thereof', and

ports communicating` with the opposite ends` of the cylinderintermediate of the exhaustports and the sul'iply-port, a dilierentialpiston-valve within said casing controlling said ports, said cylinderhaving controlling-ports communicating' with the valve-casing throughwhich fluid-pressure flows to reciprocate the valve.

In testimony whereof l sign this specification in the presence of' twowitnesses.

CHARLES H. JOHNSON. Witnesses:

Geo. L. WiLiuNsoN, C. C. CUNNINGHAM.

